This invention relates to side frames for railway car trucks, and more particularly to side frames of structural steel elements welded together.
Side frames now in general use have been produced as cast structures. Flaws of the type sometimes present in these castings are difficult to detect by any means of inspection and can lead to fatigue failures and total loss of structural integrity which could result in derailment or other serious consequences. Welded type side frames are known. However there has not been made available to railway car manufacturers welded structural steel side frames with sufficient resistance to metal fatigue to be capable of withstanding the rigorous conditions of normal operation of such equipment. Railway car manufacturers have been seeking a side frame construction that will withstand fatigue loads indefinitely as a replacement for worn and cracked cast side frames. This invention fulfills that need.